RESUMO
Nicotiana tabacum is an important and classical model plant which can respond to the change of environmental conditions by accumulating osmoprotectants, such as glycerol and proline which contribute to the re-establishment of homeostasis when exposed to various adverse environmental stresses, such as drought, salinity, high and low temperatures. The optimization of ultrasonic extraction (UE) conditions of glycerol-3-phosphate dehydrogenase (GPDH) of tobacco leaf have been built by orthogonal test. It showed that optimum of the powers, treatment times, slot times and leaf-to-solvent ratios of UE was 75w, 2h, 2s, and 1[DK]∶12 g/ml, respectively. Under these conditions, the activity of GPDH has been tested as 0.3937U/mg protein, which was higher than other extraction methods such as liquid nitrogen and grinding on ice bath. According to investigation, it is the first description of determination of content of GPDH with ultrasonic in tobacco. It could provide basis for the further research in the relation of content of glycerol and osmotic pressure in tobacco.